Lithographing press



w. R. HOTCHKISS 1,988,970

LI THOGRAPHI NG PRES S Jan. 22, 1935.

Filed April 10, 1931 6 Sheets-Sheet l Jan. 22, 1935. w. R. HOTCHKISS41,988,970

LITHOGRAPHING PRES 5 Filed April 10, 1931 6 Sheets-Sheet 2 #711 "WWW I:I i I J7 g n center Jan. 22,1935. w R HQTHK|S$ v 1,988,970

I I LITHOGRAPHING PRESS I Filed April 10. 1931 6 Sheets-Sheet 3 22,1935- w. R. HOTCHKISS LITHOGRAPHING PRESS Filed April 10, 1931 6Sheets-Sheet 4 Williwmflqyflolohkiss Jan. 22, 1935. w R o c ss I1,988,970

LITHOGRAPHING PRES S Filed April 10, 1931 6 Sheets-Sheet 5 I I /l v #7gay-11 snow Roz 9h'zzmmea wmzss 1935- w. R. HOTCHKISS 7 1,988,970

LITHOGRAPHING PRES S Filed April 10, 1931 6 Sheets-Sheet 6 gwwnlozWilliam Roy .bbhiI/ZWJSS LHP Patented Jan. 22 1935 UNITED STATES PATENTOFFICE LITHOGRAPHING PRESS William Roy Hotchkiss, St. Paul, Minn.

Application April 10, 1931, Serial No. 529,111

Claims.

, means for the sheets from the stack to the grippers which includes theautomatic registering of each sheet as the sheet travels intolithographing position, and this structure includes clutch means causingthe feeding mechanism to be inoperative from the stack, while the sheetconveying means continues to operate as long as the machine is operatingso as to carry the sheets through the press. The conveyor means isdesigned to operate to register the sheets against the register gauge soas to bring each sheet intoproper registry before it is gripped by thegripping fingers of the impression cylinder and when the sheet reachesthe position of proper registry, fingers aredesigned to hold the sameuntil the sheet has been firmly gripped by the gripping fingers, theholding fingers being designed to release automatically only after thegripping fingers began to draw the sheet around the impression cylinder.This insures the maintaining of registry of the sheets to belithographed by preventing any slipping of the sheet from the moment itreaches registry until it is lithographed.

The press includes a structure having a novel form of means forautomatically stopping the press and simultaneously throwing out ofcontact the lithographing elements in the absence of a sheet to belithographed in the press. If, for any reason in the operation of thepress, a sheet fails to be carried to the impression cylinder, thetripping mechanism of the press automatically releases the ofisetblanket cylinder which is simultaneously caused to move out of contactwith the impression plate and the lithographing cylinder. The structurefor accomplishing this result is of a different character than has beenused heretofore, having a simple and positive action. The trippingmechanism also operates an electric switch which stops the press.

The press is designed to provide a particular mounting for the plate,offset blanket and im-' pression cylinders. The plate cylinder which isand inking unit is supported in a bearing to permit vertical adjustment,and the impression cylinder is positioned below in vertical alinementwith the plate cylinder, being mounted in avertically adjustablebearing. The blanket cylinder is interposed between the plate andimpression cylinder and is held by horizontally adjustable and slidablebearings, together with locking means for holding it into and out ofoperative position with the other cylinders. This provides a means ofmounting the operating cylindersof the lithographing press so that theoperation is very simple and permits the operator to set the press moreeasily. After the press is set, accurate registry is maintainedthroughout the operation of the job even though the blanket cylinder ofthe press is repression cylinder, or for any other reason that it isfound necessary to stop the machine in the operation thereof. It isquite apparent that in some'ofiset presses in lithographing it isdiflicult to maintain accurate registry even in the operation of themachine. I believe that my simple effective structure has .overcome thisin the mounting and arrangement of the operating cylinders.

leased any time a sheet fails to vpass to the im- The press is providedwith a peculiar type of gripping fingers for the impression cylinderwhich operate to virtually rotate a half a turn in releasing andgripping a sheet to be carried over the impression cylinder. Thisstructure permits the sheets to be more easilydischarged from theimpression cylinder so that they can be carried away from the same. Theimpression cylinder is provided with lifting pins which co-operate withthe releasing of the gripping fingers.

A further feature of my press resides in the unitary arrangement of themoisture and inking unit which is provided with means for elevating thesame out of operating position without disturbing the remainder of thepress. Thus this unit may be lifted'at any time out of contact andoperation with the plate cylindera In this manner the moisture andinking unit may continue to operate elevated out of registry with theplate cylinder, thus maintaining the uniform distribution of the ink andmoisture in the same so as not to change the character by stopping ofthis unit even though it is desirable to have the ink and moisture unitout of operation with the plate cylinder.

These features together with other details, objects and advantages whichprovide a lithographing press of a character for more efficiency andeasier operation be more fully and clearating handle for elevating theinking and moisture unit. 7

Figure 5 is a diagrammatic side view of a portion of my press.

Figure 6 is a diagrammatic detail of the inking and moisture unit asamociated with the plate cylinder.

Figure 7 is a diagrammatic side view of a detail of the sheet holdingmeans.

Figure 8 is a sectional detail of the impression cylinder and the sheetholding means.

Figure 9 is a diagrammatic detail of the press tripping levers. I

Figure 10 is a similar view to Figure 9, showing the parts in adifferent position.

Figure 11 is a diagrammatic detail of the blanket cylinder locking meansand bearing.

Figure 12 is a section of the impression cylinder.

Figure 13 is an end view of the impression cylinder, showing the cam andgear means for operating the gripping fingers of the same.

Figure 14 is an end view of the opposite end of the impression cylinderto Figure 13, showing the cam means for operating the ejector pin lever.

Figure 15 is a plan view of the sheet conveyor means.-

Figure 16 is a sectional detail, showing the clutch for releasing thesheet feeding rolls at the stack table.

Figure 17 is a detail of the electric switch operating means to stop theoperation of the. machine. My lithographing press A is provided with afeeding table 10 of a desirable nature which may be provided with sidemembers 11 between which sheets may be stacked on the table 10. Thesheets are adapted to be fed from the table 10 by the feeding roller 12which is operated intermittently by the rack 13. The rack 13 is operated.by the lever 14 and the cam 15. This operates the feeding roll 12 tofeed one sheet at a time to the sheet conveying table 16 which extendsat an upward incline from the roll 12 and which is provided with sheetfeeding rolls 17 positioned adjacent the feeding roll 12.

' The cam 15 is carried by the shaft 18 which is adapted to be operatedby the clutch 19 to rotate the shaft when the clutch 19 is in operativeposition. When the clutch 19 is disengaged as illustrated in Figure 16,the shaft 18 remains stationary while the auxiliary shaft 20 mounted onthe shaft 18 continues to operate. The shaft 20 is driven by suitablechain means 21 which extends to the line of power'ofthe machine. Theclutch 19 is normally held in operative position by the coil'spring 22and by means of the hand lever 23 which projects on one side of themachine A, the clutch 19 may be disengaged by throwing the pin 24 outinto the position illustrated inFigure 16 which holds the clutch 19 openand stops the operation of the feeding roll 12 at the stack of sheets onthe table 10. This is important in this machine because it permits thefeeding of sheets from the stack or pile to be stopped while theremainder of the press A continues to operate as will be hereinaftermore fully defined.

,The sheet conveying table 16 extends at an upward incline from thesheet feeding roll 12 and from the feeder rolls 1'7 which are positionedat the lower end of the conveyor table 16. The table 16 is provided withbelt conveyors 25 which run along the surface of the table 16 on anangle inclined toward the adjustable grooved side guide 26 mounted uponthe table 16. Positioned to cooperate with the conveyor belts 25, Iprovide a series of arms 2'? which are adjustably carried on the centersupporting bar 28 and which have ball sheet contactors 29 in their outerends positioned directly above the belts 25 so as to bear against thesheets carried by the conveyor belts 25 and hold the same against theconveyor belts by the weight of the balls 29. This guides the sheetsalong the belts 25 and holds the same in frictional contact therewith sothat owing to the angular travel of the belts 25 from one end of thetable to the other and in a direction toward the grooved side guide 26,the sheets carried by the belts 25 will be brought into registry orgauged relation with the bar 26 to automatically adjust the sheets intheir travel from the table 10 along the conveyor table 16 to cause thesame to be carried up against the grooved side guide 26.

As the sheets are carried by the conveyors 25 into the press A they arecarried up against the notch 30 in the fingers which are rotatablycarried upon the shaft 32. When the sheets to be lithographed arecarried by the conveyor belts 25 along the table 16 they are brought upagainst the rotatable fingers 31 when the fingers 31 are in the dottedposition illustrated in Figure 8. These fingers stop the sheetmomentarily gauging it for forward position while the grooved side guide26 gauges the sheet for side position and as the sheets reach thisposition against the fingers 31, a pair of. sheet holding fingers 33which are carried by the pivoted link 34 depending from the supportingarm 35 come into contact with the sheet to firmly hold the same inplace. The arm 35 is operated by the levers 36 and 37 which connect withthe operating lever 38 and which are operated by the cam 39 asillustrated in Figure '7. The cam 39 is -micrometrically adjusted uponthe shaft 123 so that the operator may more accurately and easily setthe operation of the fingers 33. This is accomplished by themicrometer-yoke 124 which operates the cam 39 to set the same by meansof the ach'ustment of the micrometer screws 125.

The shaft 32 which carries the rotatable fingers 31 is operated by thelevers 40-'and 41 and which in turn are operated by the cam 42. A spring43 holds the operating levers for the fingers 33 while the spring 44holds the operating levers for the fingers 31 in normal position. Theearns 39 and 42 operate these fingers automatically in the operation ofthe machine.

The fingers 33 have an arcuated engag g surface 45 which engages againstthe sheet held on the table 16 in registry with the fingers 31 and thepivoted link 34 which supports the fingers 33 permits the fingers 33 toarcuate slightly as soon as the sheet which they are engaging begins tobe moved oif of the table 16 after thefingers 31 have been turned out ofoperative position. These fingers 33 perform an important function inholding the sheets to be lithographed against movement after the sheetshave been properly registered on the table 16 so that it is impossiblefor the sheet to getout of registry.

/istered upon the tabIe and held positively in position by the finger.s\33, the gripping fingers 46 carried by the impfiession cylinder 47 arebrought into operation to engage the edge of .the sheet projectingbeyond the inner edge 48 of the table 16 and at a period just aft r thefingers 31 have been rotated into the positiondllustrated in full linesin Figure 8. When the fingers 46 engage the sheet to carry the samearouhd the impression cylinder 47 in its operating rotation. the fingers33 do not disengage until the sheet has been pulled forward slightly bythe fingers 46 causing the fingers 33'to move arcuately just momentarilyand then the fingers 33 are released and the sheet such as B is carriedinto position to be lithographed as the cylinder 47 rotates in theoperation of the press A.

In the course of rotation of the impression cylinder 47, the sheet B isreleased from the grip of the fingers 46 when these fingers are causedto rotate away from gripping position as illustrated in Figure 12. Thesefingers 46 are operated by the cam 49 located at one end of the cylinder47 so as to operate the'segmental gear 50 which operates the gear member51 mounted upon the shaft 52 which supports the fingers 46. Thisoperating means causes the fingers 46 to rotate freely and quickly awayfrom the surface of the impression roll 47 thereby quickly freeing thesheet and carrying the fingers 46 to a position within a recess 53formed-in the cyl-. inder 47. The fingers 46 remain in this positionuntil just prior to engaging with the sheet from the edge 48 to grip thesame onto the cylinder 47. By this construction, I provide a'positiverelease for the sheets B to discharge the same onto the sheet receivingfingers 54, between which the fingers 46 rotate in their releasingoperation. The sheets are further released from the cylinder 47 by meansof the ejecting pins 55 carried in the cylinder 47 and operated by thelever 56 which rotates with the shaft 5'7. The shaft 57 is operated bythe lever 58 which engages the cam 59 to operate the ejecting pins 55into the position illustrated in Figure 12. The cam 59 is located on theopposite end of the cylinder 47 to the cam 49.

This provides a positive release for the sheets I B even though thecylinder 47 rotates rapidly and causes the fingers 46 to move away fromthe line of travel with the discharge of the sheet B.

The impression cylinder 47 is mounted in the sides of the frame of themachine A and adapted to be held vertically adjustable by the bearingboxes 60 which are readily adjusted by the screw members 61. Directly inline with this cylinder 47 I provide the plate cylinder 62 which issupported in the vertically adjustable bearing boxes 63 by the operatingscrew members 64. Thus the impression cylinder 47 "and the platecylinder,62 may be adjusted vertically in the press A when it is desiredto properly set them into operative position.

Interposed between the cylinders 47 and 62 and horizontally slidablymounted to permit antomatic releasing, I provide the blanket cylinder 65supported in the bearing boxes 66 carried in the sides of the frame ofthe machine A. This blanket cylinder is positioned in relation to thecylinders 47 and 62 so that it may be moved into operative position tocontact with the plate carried on the cylinder 62 and to lithograph ontothe sheet carried by the cylinder 47 the impression desired. The bearingboxes 66 contact with by the shaft 73.

the rods 6'7 upon which coil springs 68 are mounted, while the outer endof the rods 67 slide freely through the openings 69 in the frame of themachine A. Thus the springs 68 tend to urge the bearing boxes 66 tocarry the blanket cylinder 65 away from the cylinders 47 and 62.

I provide a locking means C to hold the cylinder 65 in operativeposition with the cylinders 47 and 62 which includes the links '70pivotally connected at '71 to the bearing boxes 66 which are adapted tobe operated by the levers '72 carried Suitable bearings 74 are providedon the frame for supporting the shaft 73 and by means of a hand lever 75the locking means C may be operated when it is desired to move thecylinder 65 into and out of operative position. When the links andthelevers 72 are positioned in line as illustrated in full lines inFigures 5 and 11, the cylinder 65 is locked in operative position toengage with the cylinders 47 and 62.

I provide an automatic releasing means D to disengage or throw thecylinder 65 out of operative position when it is desired which includesa trip lever '76 pivotally mounted at 77. The lever 76 is formed with anotch end 78 which is adapted to be engaged by the lever 79 dependingfrom the shaft 73. The compression spring means 80 engages the lever 79tending to normally urge the same downward. When the looking mechanism Cis moved by the hand operated handle into operation to set the cylinder65 in operative position, the free end of the lever 79 will engage inthe notch '78 as illustrated in Figure 10, which will slightly elevatethe outer free end 81 of the lever 76. This free end 81 of the lever76projects toward the front of the machine A, as illustrated inFigure land provides a suitable means to permit the operator of the machine A toraise the same as illustrated in the dotted out ine in Figure 10,sufficiently to release the free end of the lever-79 from the notch 78when it is desired, whereupon the springs automatically operate theshaft 73 to release the locking mechanism C. I

The tripping mechanism D is provided with a tripping plate 82 whichispivotally mounted at 83 on the block 84 which, is mounted upon the shaft77. The free end 82 of the tripping plate 82 is free to raise up when asheet to be lithographed travels along the table 16 and under the freeend 82'. However, should a sheet fail to be carried along the table 16in a manner to raise 82, then the reciprocating lever 85 which isreciprocated back and forth by the cam 86 in the machine A will'engageagainst the free end 82' and push the trip plate 82 back in a manner torotate the shaft 77 sufficiently to raise the tripping lever 76 so thatthe lever 79 will disengage from the notch '78, automatically trippingthe locking mechanism C and releasing the cylinder 65'.

The machine A is automatically stopped by the operation of the electricswitch 87 which is connected to the tripping mechanism through the shaft73 in a manner so that the switch 87 will turn off the current to themotor 88. Thus when the tripping mechanismD is operated and the lockingmechanism C is released, the motor for operating the machine A issimultaneously stopped, thereby immediately stopping theloperation ofthe machine A. This tripping 'r'neans such as D and'the operation of theblanket cylinder 65, I believe is a new structure in the construction oflithographing presses which is adaptand hold elevated the free end 82'of thetrip ed to operate in a simple and effective manner to release theblanket cylinder out of operating position and to simultaneously stopthe operation of the machine A. There are no complicated parts or detailmembers which will be apt to get out of order or which will change theoperation or registry of the machine A. The tripping mechanism ispositive in operation and automatically stops the mechanism withouteffecting the setting or adjustment of the parts.

0 The machine A is provided with a moistening and inking unit E which ismounted on the frame of. the same directly above the plate cylinder 62and has a series of ink distributing rollers 89 which are adapted tocarry the ink from the ink fountain to the plate cylinder 62. The inkfountain 90' together with the ink distributing rolls 89 and themoisture rolls 90 are carried in the sides 91 of the unit E. This entireunit is pivotally mounted at 92 in the frame of the machine A and isadapted to be operated by means of the link rods 93 which are connectedto the links 94 and adapted to be operated by the shaft 95 when thelever 96 rotates the shaft 95 in a manner to raise the unit E on one endthereof sufficiently to raise the ink distributing and moisture rollsaway from the plate cylinder 62. This structure is illustrated in-Figures 3, 5 and 6. The lever 96 operates in conjunction with thequadrant 9'7 so that the spring pin 98 carried by the free end of thelever 96 is adapted to engage in openings such as 99. formed in thequadrant to lock the unit E either in operating or inoperative position.

In the operation of the machine A it is only necessary for the operatorto engage the free end of the lever 96, disengage the pin 98 from one-0f the openings 99, and press down on the lever 96, and this will raisethe link rods 93. thereby raising the unit E as illustrated in Figure 6,away from the plate cylinder 62. The rollers of the unit E may continueto operate ,with the-operation of the machine even though they areelevated, and' thus they maintain the proper distribution of the ink andmoisture on the rolls in the unit E so that they maybe instantly broughtinto operative relation with the cylinder 62. The unit E moves butslightly. This slight movement is sufficient to space the unit from thecylinder 62, but is not sufficient to disengage the unit from thedriving gears, so that the unit E continues to operate when in theposition illustrated in Figure 6. I have found this feature verydesirable in the operation of my lithographing press A. j

Certain rollers of the unit E are adapted to be oscillated by the cam100, as illustrated in Figure 2. which raises the link 101 up and downto oscillate the shaft 102, and the shaft 102 in turn oscillates thelevers 103 and 104. The shaft 103 is provided with a roller 105 on theend which engages between flanges 106 to oscillate the shaft 107. Thelever 104 is provided with a roller 108 which operates between theflanges 109 to oscillate the shaft- 110 and by means of the link inkingand moisture units, insofar as I know,

the method of operating the rollers of the unit E to oscillate the sameas just described, I believe has never been ,done, and particularly inconjunction with the pivoted unit E which may be elevated away from theplate cylinder and may continue to operate so that the ink and moisturecarried by the unit E is evenly carried through the unit beingconstantly worked to keep the same in readiness for immediate operationas soon as the lever 96 is operated to release the unit E into operativeposit-ion with the plate cylinder 62.

The lithographing press A is provided with a micrometrically adjustablegauge F which is positioned above the .table 16 and is provided with agauge bar 117 pivotally supported at 118 and adapted to be adjusted bythe set screws 119 and 120. The screws 119 and 120 may be adjusted tomicrometrically set the arcuated edge 121 in relation to the table 16 sothat only one sheet at a time may pass beneath the edge 121 intoregistry to be engaged by the gripping fingers 46. The tripping plate 82is positioned in the table 16 beyond this gauge F so that should anysheets pile up at the gauge bar 11'? thereby preventing the sheets frompassing beyond the gauge, the machine will be automatically tripped tostop the same.

The lithographing machine A has been designed and operated to carry outthe principles set forth so as to provide a machine of this characterwhich may be easily operated and maintained in lithographing sheets in apractical manner.- thoroughly tried and tested in actual operation andhave been found to provide advantages over structures used heretofore inlithographing presses. My lithographing press A will operate to maintainregistry I believe more accurately and provides a simple structure withfewer parts which may be readily and easily adjusted. In the operationshould it be desired to stop the feeding of sheets off of the table 10,it is only necessary for the operator to disengage the clutch 19permitting the remainder of he machine to continue to operate so as tocarry any sheets which are already in the press on through the same.This permits the sheets to be cleared out of the machine.

During the operation of the machine A, either the absence of a sheet inthe press to be carried to the impression cylinder or the lifting of thetripping lever '76 by the operator will cause the blanket cylinder 65 tobe automatically released out of operating position, thereby preventingoverinking of the blanket or getting ink on the impression roll. Theabsence of the sheet in the machine to be lithographed may stop theentire machine simultaneously with the releasing of the lock C or theoperating parts of the electric switch 8'7 which controls the operationof the machine A may be set so as not to be operated by the releasing ofthe cylinder 65, permitting the machine to continue to operate after thecylinder 65 has been released out of operating position. Further, theoperator may elevate the inking and moisture unit E at any time yetpermitting theparts of the unit to continue to operate the rolls of thesame without contacting with the plate cylinder 62, keeping the ink andmoisture in this unit ready for instant operation. These features are ofprimary importance in the operation of my lithographing machine A.

In accordance with the patent statutes, I have described the principlesof operation of my litho- All of the features set forth have beengraphing press and while I have illustrated a 1 from the spirit of theinvention and within the scope of the following claims.

I claim:

l. A lithographing press including, a plate cylinder, an impressioncylinder, means for adjusting said cylinders vertically, a blanketcylinder associated with said plate and impression cylinders and enageable therewith, means for looking said blanket cylinder in operativeposition with said plate and impression cylinders, means for releasingsaid blanket cylinder, and springmeans for automatically moving the samesimultaneously an equal distance out of engagement with said plate andimpression cylinders.

2. A lithographing press including, a plate cylinder, an impressioncylinder for receiving sheets to be lithographed vertically aligned withsaid plate cylinder, a blanket cylinder, said plate and impressioncylinders being adjustable vertically, means for horizontally slidingsaid blanket cylinder into operative position with said plate andimpression cylinders, means for locking said blanket cylinder intooperative position, spring means for moving said blanket cylinder out ofoperative position, and tripping means for releasing said locking meansfor said blanket cylinder operated by the absence of a sheet to belithographed in said press.

3. A lithographing press including, a plate cylinder, an'impressioncylinder, a blanket cylinder interposed in a manner to be slid into andout of operation with said plate and impression cylinders simultaneouslywhile said plate and impression cylinders remain operatively fixed,means supporting said blanket cylinder slidable substantially normallyto a plane through the axes of the plate and impression cylinders, meansfor adjusting said plate andimpression cylinders to register with theblanket cylinder when said blanket cylinder is in operative position,means for locking said blanket cylinder in operative position, andspring 'means for pushing said blanket cylinder out of operatingposition when said locking means is released:

4. A lithographing press comprising, a frame. a plate cylinder, animpression cylinder, an inking and moisture unit associated withsaidplate cylinder, inking and moisture rollers in said unit, means forlifting said unit out of operative contact with said plate cylinder, andmeans for rotatably engaging each of said rollers to rotate said rollerswhen in or out of contact with said plate cylinder.

5. An offset lithographing press including, a frame, a plate cylinder,an impression cylinder, an ink feeding and moisture unit associated withsaid plate cylinder, means for pivoting said unit to said frame, andmeans for elevating said unit out of contact with said plate cylinderand means for operatively connecting the parts of said unit in or out ofcontacting position.

6. The combination, a printing press, a frame, a-plate cylinder, animpression cylinder, sheet gripping fingers carried by said impressioncylinder, vertically adjustable bearings supported in said frame, meansfor adjusting said hearings in said frame to adjust the position of saidplate and impression cylinders in relation to each other, a blanketcylinder, slidable bearings positioned ,in said frame for supportingsaid blanket cylinders and locking means for forcing and holding saidblanket cylinder operatively contacting with said plate and impressioncylinders.

7. A lithographing press including, a rotary stop for retarding eachsheet in its passage to the press, fingers for engaging the sheetsimultaneously with the engagement with said rotary stop adapted to holdthe sheet stationary in proper registered position within said press,means for operating said rotatable stop out of operative position, animpression cylinder, means for gripping the sheet to draw the same oversaid impression cylinder, said sheet engaging fingers having anoscillatory movement to move with the sheet slightly before disengagingtherefrom as the same is drawn on to the impression cylinder.

8. A lithographing press including, an impression cylinder, grippingfingers carried by said cylinder, means for rotating said grippingfingers into andout of operating position, a recess into which saidfingers are adapted to be embedded when out of operating position formedin said inder, an impression cylinder, an offset blanket cylinder, meansfor slidably supporting said blanket cylinder to be operated into andout of simultaneous engagement with said plate and impression cylinders,a member continuously moving with the press, and trip means pivotal.into position to be engaged by said member in the absence of a sheet insaid press to be lithographed on to automatically trip said offsetblanket cylinder out of operative position.

10. A lithographing press comprising, a plate cylinder, an impressioncylinder, a-blanket cylinder interposed between the mounting points ofsaid plate and impression cylinders and .having its bearings slidablysupported oifset from the bearings of said plate and impressioncylinders, spring means for urging the bearings of said blanket cylinderto move the same away from said plate and impression cylinderssimultanei ously, locking means for holding said blanket cylinderoperatively against said plate and impression cylinders, sheet feedingmeans] in said press, trip means interposed in the path of travel of thesheet in said sheet feeding means, means I engageable with said tripmeans in the absence 1 11. A lithographing press including, oifset.lithographing means, means for driving said lithographing press, meansrendered inoperative by the presence of a sheet being fed to the pressfor releasing the oifset mechanism of. said press out of contact withthe remainder of said lithographing means, and means for simultaneouslystopping said driving meansfor said press.

12. A lithographing press including, a plate cylinder, a blanketcylinder, an impression cylinder, said blanket cylinder being slidablypositioned to be operated" into and out of contact with said plate andimpression cylinders, m ans for locking said blanket cylinder to contactwith said plate and impression cylinders, electrical means for operatingsaid press, an electric switch for controlling said electrical operatingmeans, a sheet controlled tripping means including means forsimultaneously tripping said blanket cylinder out of operating positionand to stop said electrical operating means in the absence of a sheet insaid press to be lithographed. 13. A lithographing press including, anofiset cylinder having blanket, plate and impression cylinders, meansfor holding said oiiset cylinder locked into operative position withsaid plate and impression cylinders, spring means for pushing saidoffset cylinder at an equal angle away from said plate and impressioncylinders simultaneously when said lock is released, and hand operatedtripping means for releasing said lock to automatically release saidoilset cylinder out of contact with said plate andimpression' cylinders.14. A lithographing press including, plate and impression cylinders,means for vertically adjusting and supporting said cylinders in axialalignment, an offset blanket cylinder horizon tally slidably supportedto one side of the axial alignment of said plate and impressioncylinders, means for locking said blanket cylinder in contact with saidplate and impression cylinders, spring means for urging said blanketcylinder simultaneously out of operative position with said cylinders,hand operated lever means for setting said locking means in operativeposition, a sheet feeding conveyor and table, a sheet trip positionedwithin said table for tripping said locking means, and a reciprocatinglever engageable to operate said trip in the absence of a, sheet to belithographed to release said blanket cylinder out of operative pwitionby said spring means.

15. A lithographing press including, a lithographing means for sheets,means for feeding and registering sheets in said press, a trip torelease said lithographing means out of operative position adapted to beoperated by the sheets fed into said press by said sheet feeding means,a

reciprocating lever for operating said trip, said trip being pivotallymounted to be held elevated out of tripping position with saidreciprocating lever when a sheet is disposed on said sheet feedingmeans.

offset cylinder in operative position, and means for moving said offsetcylinder out of operating position automatically by the absence of asheet at the moment of registration in said press including acontinuously moving member anda trip engageable with said member in theabsence of a sheet.

17. A lithographing press including, an offset blanket cylinder, meansfor slidably mounting said blanket cylinder, means for locking said011'- set cylinder into operative position, spring means for moving saidblanket cylinder out of operative position,'a plate cylinder, animpression cylinder, means for adjusting said plate and impressioncylinders to contact with said blanket cylinder when the latter islocked in operative position, means for automatically releasing saidblanket cylinder simultaneous out or engagement with said plate andimpression cylinders by the absence of a sheet in registered position insaid press, and means for independently operating said releasing meansof said sheet operating means by hand by the operator of said press.

18. A lithographing press including, plate, im-

pression and offset cylinders, means for locking said offset cylinderinto engagement with said plate and impression cylinders, spring meansfor throwing said oflset cylinder out of operative position when saidlocking means is released, said locking means including a triggermember, means for holding said triggerunder spring tension, areciprocating lever, means on said holding means engageable by saidreciprocating'lever .to release said trigger, said last named meansrendered ordinarily inoperative by the presence of a sheet of paperbetween this means and said reciproeating lever.

19. A lithographing press including, plate, impression and blanketcylinders, means for releasing said blanket cylinder from engagementwith said plate and impression cylinders including, a trigger operableto release said blanket cylinder, means for holding said trigger underspring tension, a reciprocating lever, and means on said holding meansfor engagement by said reciprocablelever when a sheet is not fed to thepress to trip said trigger and. to release said blanket cylinder.

20. A lithographing press including, cylinders, means for removing onecylinder from operative position, and for holding said cylinder inoperating position, means comprising a pair of pivoted toggle leverspivotal into longitudinal alignment to hold said cylinder in operativeposition and pivotal into relative angularity to release said cylinder.

' ,WILLIAM ROY HOTCHKISS.

